It is sometimes required to perform maintenance or inspect utility poles and their components. When the utility pole being worked on supports overhead power lines, it is sometimes necessary to disable the power lines so that the work can be performed safely.
Such utility poles therefore have one or more disconnectors, which are used to ensure that an electrical circuit, for instance in a branch of a power network, is completely de-energised for service or maintenance. The disconnectors can be operated either manually, or can be motorized. Typically, disconnectors are known as “off-load devices” because they are opened only after current has been interrupted by some other control device. Disconnectors generally employ safety devices to prevent inadvertent operation. Some may require a key or similar failsafe, to confirm that the technician actually intends to activate it.
Some safety devices for disconnectors require that the technician be raised to the height of the disconnector in order to attach the safety device, which can be time consuming and potentially hazardous. Furthermore, some safety devices are not easily attached to the disconnector, or require complex locking mechanisms to prevent use of the disconnector.